Tapinarof

Risk Summary

The available data on tapinarof cream use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. In animal reproduction studies, subcutaneous administration of tapinarof to pregnant rats and rabbits during the period of organogenesis resulted in no significant adverse effects at doses 268 and 16 times, respectively, the maximum recommended human dose (MRHD) (see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of major birth defects, loss, and other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

In an embryofetal development study in rats, tapinarof was administered by subcutaneous injection to pregnant animals at doses of 1.2, 6.9 and 34 mg/kg/day during the period of organogenesis. Tapinarof was not associated with embryofetal lethality or fetal malformations. Tapinarof increased the incidence of skeletal variations (incomplete ossification of nasal bones) at the dose of 34 mg/kg/day (268 times the MRHD based on AUC comparisons).

In an embryofetal development study in rabbits, tapinarof was administered by subcutaneous injection to pregnant animals twice daily at doses of 0.3, 1, and 3 mg/kg/day during the period of organogenesis. Maternal toxicity as evidenced by decreased maternal body weight gain and associated increased post-implantation loss (embryolethality) was observed at 3 mg/kg/day. In addition, fetal skeletal variations were observed at 3 mg/kg/day. Tapinarof was not associated with embryofetal lethality or fetal malformations at doses up to 1 mg/kg/day (16 times the MRHD based on AUC comparison) or fetal malformations at doses up to 3 mg/kg/day (30 times the MRHD based on AUC comparison).

In a second embryofetal development study in rabbits, tapinarof was administered by continuous subcutaneous infusion to pregnant animals at doses of 1, 2 and 3 mg/kg/day during the period of organogenesis. Tapinarof was not associated with embryofetal lethality or fetal malformations at doses up to 3 mg/kg/day (20 times the MRHD based on AUC comparison).

In a prenatal and postnatal development study, tapinarof was administered by subcutaneous injection to pregnant rats at doses of 1, 6 and 30 mg/kg/day beginning on gestation day 6 through lactation day 20. Maternal toxicity associated with decreases in body weight gain and food consumption was noted at 30 mg/kg/day (268 times the MRHD based on AUC comparisons). Tapinarof decreased fetal survival and viability that resulted in reduced litter sizes and decreased fetal weights at doses greater than or equal to 6 mg/kg/day (45 times the MRHD based on AUC comparisons). No tapinarof-related effects on fetal survival and viability were noted at a dose of 1 mg/kg/day (6 times the MRHD based on AUC comparisons). No tapinarof-related effects on postnatal development, neurobehavioral or reproductive performance of offspring were noted at doses up to 30 mg/kg/day (268 times the MRHD based on AUC comparison).

Risk Summary

No data are available regarding the presence of tapinarof in human milk or the effects of tapinarof on the breastfed infant, or on milk production. Tapinarof was detected in rat offspring following subcutaneous administration to pregnant female rats which suggests that tapinarof was transferred into the milk of lactating rats (see Data). When a drug is present in animal milk, it is likely that the drug will be present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for tapinarof cream and any potential adverse effects on the breastfed infant from tapinarof cream or from the underlying maternal condition.

Data

In a prenatal and postnatal development study, tapinarof was administered by subcutaneous injection to pregnant rats at doses of 1, 6, and 30 mg/kg/day from gestation day 6 through lactation day 20. Tapinarof was quantifiable in offspring plasma samples on postnatal day 10 at doses of 6 and 30 mg/kg/day, suggesting that tapinarof is present in animal milk.

Long-term carcinogenicity studies were conducted in mice (daily topical administration at doses of 0.5, 1.5 and 3% tapinarof cream) and in rats (subcutaneous administration at doses of 0.1, 0.3, and 1 mg/kg/day tapinarof). No drug-related neoplasms were noted in mice after 98 (females) to 102 (males) weeks of daily topical administration at doses up to 3% tapinarof cream (44 times the MRHD based on AUC comparisons). No drug-related neoplasms were noted in female rats after 83 weeks of daily subcutaneous administration at doses up to 1 mg/kg/day tapinarof (9 times the MRHD based on AUC comparisons).

Tapinarof revealed no evidence of mutagenicity or clastogenicity in an Ames assay, an in vitro mammalian chromosomal aberration assay, an in vitro mouse lymphoma assay and two in vivo micronucleus assays in mice and rats.

Tapinarof did not impair female fertility at subcutaneous doses up to 30 mg/kg/day (268 times the MRHD based on AUC comparisons).

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In two randomized, double-blind, multicenter, vehicle-controlled clinical trials (PSOARING 1 and PSOARING 2), 1025 adults with plaque psoriasis were treated with tapinarof cream or vehicle cream once daily for up to 12 weeks.

Subjects ranged in age from 18 to 75 years, with an overall median age of 51 years. The majority of subjects were white (85%) and male (57%); and 85% were non-Hispanic or Latino.

Table 1 presents adverse reactions that occurred in at least 1% of subjects treated with tapinarof Cream, and for which the rate exceeded the rate for vehicle.

Table 1. Adverse Reactions Occuring in ≥1% of the Subjects in the 12-week PSOARING 1 and PSOARING 2 Clinical Trials:

^a Folliculitis includes application site folliculitis and folliculitis
^b Nasopharyngitis includes nasopharyngitis, nasal congestion, pharyngitis, respiratory tract infection (RTI) viral, rhinorrhea, sinus congestion, upper RTI, and viral upper RTI
^c Contact dermatitis includes dermatitis, contact dermatitis, hand dermatitis, and rash
^d Headache includes headache, migraine, and tension headache
^e Pruritus includes application site pruritus, pruritus, generalized pruritus, and genital pruritus
^f Influenza includes influenza and influenza-like illness

Two (0.3%) subjects using tapinarof cream developed urticaria. Adverse reactions leading to treatment discontinuation in >1% of subjects who received tapinarof cream were contact dermatitis (2.9%) and folliculitis (2.8%).

In an open label safety trial (PSOARING 3), 763 subjects were treated for up to an additional 40 weeks after completing PSOARING 1 or PSOARING 2. In addition to the adverse reactions reported in the 12-week PSOARING 1 and PSOARING 2 clinical trials, the following adverse reactions were reported: urticaria (1.0%) and drug eruption (0.7%).